Equipment and method for the production of cardboard tubes

ABSTRACT

Equipment for the production of cardboard tubes, comprising a tube-forming machine (1) provided with means for forming cardboard tubes with strips of cardboard (3) helically wound on a forming spindle (10), comprising a feeding unit (2) for feeding said cardboard strips, and comprising guide means (4) for guiding the cardboard strips (3) along a predetermined path (30, 31, 32) between the feeding unit (2) and the tube-forming machine (1), wherein in a final section (32) of said path the strips of cardboard (3) enter into the tube-forming machine (1). The guide means (4) are arranged and acting, along the said path, such that in said final section (32) of said path the cardboard strips (3) enter from the above or from the bottom into the tube-forming machine (1), so that said final section (32) is a descending or an ascending section of said path.

The present invention relates to an equipment and a method for theproduction of cardboard tubes, in particular for the paper convertingindustry.

It is known that in paper converting plants a “tube-forming” machineproduces rigid cardboard tubes (also called “core”) on which the paperis wound to form a roll or “log” which is subsequently divided into moreelements having a predefined length in order to obtain rolls of toiletpaper, rolls of kitchen paper etc.

Each tube is obtained from strips of cardboard, fed by correspondingreels, which are helically wound on a metal spindle with horizontal axisand glued one on the other so as to form a self-supporting tubularstructure. Generally, use is made of two or three strips of cardboard,depending on the desired thickness of the cores to be produced. It isalso possible to produce tubular cores from a single cardboard strip andhave customized cardboard feeding units. The cardboard strips arepartially superimposed on each other and, by means of an eight-shapedbelt they are wound on two guide rollers, are rolled around the mandreland pushed forward, thus obtaining the tubular cardboard core thatadvances along the same spindle. Said belt wraps also around the spindleso as to engage the strips of cardboard.

Through a suitable cutting unit, the tubular cardboard core is cut to apredetermined length which substantially corresponds to the length ofthe logs to be produced by other machines that are normally called“rewinders”.

The cardboard strips come from feeding units comprising reels from whichthe same cardboard strips are unwound, following a direct path betweeneach feeding unit and the spindle of the tube-forming machine. Since thespindle is normally positioned at about one meter above the basement ofthe tube-forming machine, the space between the cardboard feeding unitsand the tube-forming machine is occupied by the cardboard strips.Therefore, it is not possible to position the cardboard feeding unitsand the tube-forming machine opposite to one another, otherwise theoperators are not allowed to move freely between them, and thepositioning of the cardboard feeding units and the tube-forming machinesrequires a wider space.

The main purpose of the present invention is to eliminate, or at leastgreatly reduce, the aforementioned drawbacks.

This result is achieved, according to the present invention, by adoptingthe idea of providing an apparatus and implementing a method having thecharacteristics indicated in the independent claims. Other features ofthe present invention are object of the dependent claims.

Thanks to the present invention, it is possible to have the cardboardfeeding unit and the tube-forming machine facing one another without,however, preventing an operator to move freely between them and,therefore, obtaining the advantage of placing the cardboard feeding unitand the tube-forming machine according to a most efficient arrangement.In addition, the implementation of the present invention requires a verylow expenditure in relation to the benefits.

These and other advantages and features of the present invention will bemore understood by anyone skilled in the art from the followingdescription and with the aid of the attached drawings, given as apractical exemplification of the invention, but not to be considered ina limiting sense, in which:

FIG. 1 is a schematic side view of an equipment according to the presentinvention;

FIG. 2 is a schematic view from the above of the equipment shown in FIG.1;

FIG. 3 is a scheme that shows the path followed by the cardboard strips;

FIG. 4 shows another arrangement of the reels by which the cardboardstrips are supplied.

Reduced to its basic structure and with reference to the attacheddrawings, the equipment according to the present invention comprises atube-forming machine (1) and a feeding unit (2) that supplies thetube-forming machine with the cardboard required for forming thecardboard tubes. The tube-forming machine (1) and the feeding unit (2)are known per se. In particular, with reference to the example shown inthe attached drawings, the tube (1) is of the type comprising a spindle(10) served by a belt (11) wound on two pulleys (12) so as to form a“8”-shaped figure. One of said pulleys is connected to a gear motor(13), while the other pulley is free to rotate about its own axis. Theunit constituted by the gear motor (13), the pulleys (12) and thespindle (10) is supported by a structure (14) protected by a casing(15). The belt (11) drags the glued cardboard strips (3) coming from thesupply unit (2) and wounds them on the spindle (10), making themsimultaneously move parallel to the longitudinal axis of the spindle. Atube-forming machine of this type is described, for example, in WO95/10400 and WO 95/10399.

The feeding unit (2) is of the type comprising a support structure (20),which, on one side (2A), supports one or more reels (21) with horizontalaxis (22) from which the cardboard strips (3) are unwound and, on theother side (2B)supports a series of rollers for guiding and tensioningthe cardboard strips (3) and a plurality of tanks containing liquid gluethat is applied on a lower side of the same cardboard strips (3) draggedby the belt (1) as disclosed above. The structure (20) has a series ofslits (25) through which the cardboard strips (3) of the reels (21) canpass from the side (2A) to the side (2B) of the structure (20). Inpractice, while advancing along a direction (D) parallel to the side(2B) of the structure (20), the strips of cardboard (3) receive apredetermined quantity of liquid glue on their lower side. A feedingunit so structured and functioning is described in U.S. Pat. No.7,407,470.

Advantageously, according to the present invention, the tube-formingmachine (1) and the feed unit (2) are provided with guide means adaptedto force the cardboard strips (3 to enter the tube-forming machine (1)from the above. For example, the said guide means are constituted byrollers (4) respectively placed on the second side (2B) of the structure(20) and on top of the casing (15). In this way, the tube-formingmachine (1) and the feed unit (2) can be placed one opposite the other(as shown in FIG. 2) and the space between the tube-forming machine (1)and the feed unit (2) is freely accessible, so there is a more rationalarrangement of the machines and an operator (M) can move freely betweenthem to operate both the machines without being forced to constantlymove around them.

In FIG. 3, a strip of cardboard (3) follows a path that has a firstsection (30) between a slot (25) of the structure (20) and a point at apredetermined height relative to the floor (P) on which rest the feedunit (2) and the tube-forming machine (1), a second section (31)overhanging the space between the feed unit (2) and the tube-formingmachine (1), and a third section (32) which, from above, enters thetube-forming machine (1) from an upper opening of the casing (15) andreaches the spindle (10). For example, the said second section (31) isat a height greater than 1.70 m above the floor.

In FIG. 2 the cardboard tube that comes out of the tube-forming machine(1) is denoted by the reference “T”.

FIG. 2 shows, in particular, the tube-forming machine (1) and the feedunit (2) with the spindle (10) oriented parallel to the axis (22) thatsupports the reels (21), so that the tube-forming machine (1) and thefeed unit (2) are positioned perfectly opposite to one another.

In accordance with the present invention, a method for the production ofcardboard tubes, comprises the use of a tube-forming machine (1)provided with means for forming cardboard tubes with strips of cardboard(3) wrapped helically about a forming spindle (10), comprises the use ofa unit (2) for feeding said cardboard strips, and comprises the use ofguide means (4) for guiding the cardboard strips (3) along apredetermined path (30, 31, 32) between the feed unit (2) and thetube-forming machine (1), wherein in a final leg (32) of said path thestrips of cardboard (3) enter the tube-forming machine (1), and in saidfinal leg (32) the cardboard strips (3) enter from the above into thetube-forming machine (1), whereby said final leg (32) is a descendingleg of said path.

An intermediate leg (31) of said path (30, 31, 32) is above a spacebetween the tube-forming machine (1) and the feed unit (2).

A solution equally advantageous according to the present inventionimplies a different positioning of the intermediate leg (31) which,rather than above the space between the tube-forming machine (1) and thefeed unit (2), is at a height less than a predetermined value (forexample, at a height less than 30 cm) above the floor. In this case, thefinal leg (32) is an ascending part of said path. To avoid that theoperator is obstructed by said intermediate leg, in this case it can bearranged a step that allows the same operator to pass over theintermediate leg when this is necessary. Or, in this case, saidintermediate leg (31) can run in a box-shaped guide provided in thefloor.

In each of the two cases described above, that is, both in the case thatthe intermediate leg (31) of said path is above the space between thetube-forming machine (1) and the feed unit (2), and in the case thatsaid intermediate leg (31) is at a level sufficiently low to allow theoperator to move freely between the tube-forming machine (1) and thefeed unit (2), the desired result is obtained.

According to the example shown in FIG. 4, the reels (21) feeding thestrips of cardboard (3) are positioned with their axes orientedperpendicular to the axis of the spindle (10), so that the productionsystem as a whole is further compacted.

In practice the details of execution may vary in any equivalent way asfor what concerns the individual elements described and illustrated, andtheir mutual arrangement, without departing from the scope of theadopted solution and thus remaining within the limits of the protectiongranted to the present patent.

The invention claimed is:
 1. Equipment for producing cardboard tubes,the equipment comprising: a tube-forming machine comprising a means forforming cardboard tubes with strips of cardboard helically wound on aforming spindle; a feeding unit for feeding said cardboard strips; and aguide means for guiding the cardboard strips along a predetermined pathbetween the feeding unit and the tube-forming machine, wherein in afinal section of said predetermined path the strips of cardboard enterinto the tube-forming machine, said guide means being arranged andacting, along the predetermined path, such that in said final section ofsaid predetermined path the cardboard strips enter from above thetube-forming machine or from a bottom of the tube-forming machine intothe tube-forming machine, so that said final section is a descending oran ascending section of said predetermined path, the tube-formingmachine producing cardboard tubes being adapted to collect paper thereonto form paper logs from which paper rolls are obtained, said pathfurther comprising a first section exiting from said feeding unit and anintermediate section comprised between said first section and said finalsection of said path, wherein a free space is defined between saidfeeding unit and said tube-forming machine, said free space beingentirely free of strips, said intermediate part of said path is above orbelow said free space, said cardboard strips being fed each by arespective bobbin from which said cardboard strips are drawn, saidcardboard strips being configured to be helically wound on said formingspindle of said tube-forming machine, wherein no structure is providedin said free space between said feeding unit and said tube-formingmachine and no strips of cardboard pass through said free space.
 2. Theequipment according to claim 1, wherein said tube-forming machinecomprises an outer casing and said feeding unit comprises a supportingstructure supporting one or more bobbins from which the cardboard stripsare drawn, said means for guiding the strips of cardboard comprising aplurality of rollers arranged at a predetermined height from a surfaceon which the tube-forming machine and the feeding unit rest.
 3. Theequipment according to claim 1, wherein an intermediate section of saidpredetermined path is above a space comprised between the tube-formingmachine and the feeding unit or said intermediate section is at a heightlower than a predetermined value with respect to a surface on which thetube-forming machine and the feeding unit rest.
 4. The equipmentaccording to claim 1, wherein the cardboard strips are drawn fromcorresponding bobbins mounted on respective shafts supported by a fixedstructure of the feeding unit, said shafts being parallel or orthogonalto said forming spindle.
 5. A method for producing cardboard tubes, themethod comprising: using a tube-forming machine comprising a means forforming cardboard tubes with strips of cardboard helically wound on aforming spindle; using a feeding unit for feeding said cardboard strips;and using a guide means for guiding the cardboard strips along apredetermined path between the feeding unit and the tube-formingmachine, wherein in a final section of said predetermined path thestrips of cardboard enter into the tube-forming machine, wherein in saidfinal section of said predetermined path the cardboard strips enter fromabove the tube-forming machine or from a bottom of the tube-formingmachine into the tube-forming machine, so that said final section is adescending or an ascending section of said predetermined path, thetube-forming machine producing cardboard tubes being adapted to collectpaper thereon to form paper logs from which paper rolls are obtained,said path further comprising a first section exiting from said feedingunit and an intermediate section comprised between said first sectionand said final section of said path, wherein a free space is definedbetween said feeding unit and said tube-forming machine, said free spacebeing entirely free of strips, said intermediate part of said path beingabove or below said free space, said cardboard strips being fed each bya respective bobbin from which the cardboard strips are drawn, thecardboard strips being configured to be helically wound on the formingspindle of the tube-forming machine, wherein no structure is provided insaid free space between said feeding unit and said tube-forming machineand no strips of cardboard pass through said free space.
 6. The methodaccording to claim 5, wherein an intermediate section of saidpredetermined path is above a space comprised between the tube-formingmachine and the feeding unit.
 7. The method according to claim 5,wherein an intermediate section of said predetermined path is at aheight lower than a predetermined value with respect to a surface onwhich the tube-forming machine and the feeding unit rest.
 8. Equipmentfor producing cardboard tubes, the equipment comprising: a tube-formingmachine producing cardboard tubes with strips of cardboard helicallywound on a forming spindle; a feeding unit for feeding said cardboardstrips, the feeding unit comprising a reel; a support structuresupporting the feeding unit, the support structure comprising a supportstructure portion extending from at least a first support structureportion position to a second support structure portion position, thefirst support structure portion position being located adjacent to thereel, the second support structure portion position being located at aheight greater than a height of the reel; and a guide structure defininga cardboard strip delivery path extending from at least a first positionto at least a second position, the first position being located directlyadjacent to the second support structure position, the second positionbeing located above the tube-forming machine, wherein at least a portionof the cardboard strip delivery path is provided between the feedingunit and the tube-forming machine, the portion of the cardboard stripdelivery path spanning a space between the feeding unit and thetube-forming machine, the portion of the cardboard strip delivery pathbeing located above the space, wherein no strips of cardboard arelocated in the space below the portion of the cardboard strip deliverypath, each and every part of the portion of the cardboard strip deliverypath having a height greater than a height of the tube-forming machine,wherein in a final section of the cardboard strip delivery path thestrips of cardboard enter into the tube-forming machine from the secondposition located above the tube-forming machine, the cardboard stripsbeing fed each by a respective bobbin from which the cardboard stripsare drawn, the cardboard strips being configured to be helically woundon the forming spindle of the tube-forming machine, wherein no structureis provided in the free space between the feeding unit and thetube-forming machine and no strips of cardboard pass through the freespace.
 9. The equipment according to claim 8, wherein the final sectionis a descending or an ascending section of the cardboard strip deliverypath, the tube-forming machine producing cardboard tubes being adaptedto collect paper thereon to form paper logs from which paper rolls areobtained.
 10. The equipment according to claim 9, wherein thetube-forming machine comprises an outer casing and the feeding unitcomprises a supporting structure supporting one or more bobbins fromwhich the cardboard strips are drawn, the guide structure comprising aplurality of rollers arranged at a predetermined height from a surfaceon which the tube-forming machine and the feeding unit rest.
 11. Theequipment according to claim 9, wherein an intermediate section of saidpredetermined path is above the space between the tube-forming machineand the feeding unit, at least a portion of the space being free of thetube-forming machine and the feeding unit.
 12. The equipment accordingto claim 9, wherein the cardboard strips are drawn from correspondingbobbins mounted on respective shafts supported by a fixed structure ofthe feeding unit, the shafts being parallel or orthogonal to the formingspindle.
 13. The equipment according to claim 10, wherein the firstposition is located above the bobbins and the first position is locatedadjacent to an uppermost portion of the supporting structure.
 14. Theequipment according to claim 9, wherein the tube-forming machinecomprises an outer casing, the second position being located at aposition above an upper portion of the outer casing.
 15. The equipmentaccording to claim 9, wherein a height of the first position is greaterthan a height of the second position.
 16. The equipment according toclaim 9, wherein the height of the portion of the cardboard stripdelivery path comprises a cardboard strip delivery path height, thecardboard strip delivery path height being greater than a height of thesecond position.
 17. The equipment according to claim 16, wherein thetube-forming machine comprises an outer casing, wherein an uppermostportion of the outer casing has an outer casing height, the cardboardstrip delivery path height being greater than the outer casing height.18. The equipment according to claim 16, wherein the portion of thecardboard strip delivery path is inclined between the first position andthe second position.
 19. The equipment according to claim 9, wherein theheight of the portion of the cardboard strip delivery path decreasesfrom the first position to the second position.
 20. The equipmentaccording to claim 9, wherein the portion of the cardboard stripdelivery path has a downward slope from said first position to saidsecond position.